POS0229 COMBINING MTX DOES NOT RESULT IN AN ADDITIONAL EFFICACY OF UST TREATMENT IN POLYARTHRITIC PSA: SUBGROUP ANALYSIS FROM A RANDOMIZED PLACEBO-CONTROLLED INVESTIGATOR INITIATED CLINICAL TRIAL
Authors: M. Köhm, A. C. Foldenauer, T. Rossmanith, H. Kellner, U. Kiltz, A. Kleyer, G. R. Burmester, J. Brandt-Juergens, D. M. Kofler, H. Burkhardt, F. Behrens
Journal: Annals of the Rheumatic Diseases (2023)

<h3>Background</h3> BDMARD treatment in PsA patients usually requires treatment failure/intolerance to csDMARDs. The value of MTX in combination with bDMARDs is still unclear; an increase of efficacy is expected in polyarthritis. We designed an investigator-initiated, randomized, placebo-controlled trial (IIT) in active PsA to examine if outcomes of UST in combination with MTX (either newly initiated or ongoing) are different from UST only (+PBO), especially with focus on peripheral arthritic dominant PsA. <h3>Objectives</h3> To compare ACR20/50/70 and MDA response rates at week 24 in treatment groups stratified by number of affected joints (oligo- vs polyarthritis). <h3>Methods</h3> 186 patients with active PsA (defined as TJC≥4, SJC≥4 [68/66 joint count] and DAS28≥3.2) were screened for eligibility, 173 patients were randomized to UST+MTX (new or ongoing) or UST+PBO. 166 patients were included into the analysis. The cohort was stratified by number of affected joints: oligoarthritis (&lt; 5 joints) and polyarthritis (≥ 5 joints.); for polyarthritis with additional subgroups (5-7, 8-10 and with &gt;10 joints affected). Response rates (ACR20, 50, 70 response, MDA and 50% reduction in SJC/TJC) were calculated. <h3>Results</h3> BL data were well-balanced between treatment groups/subgroups (table 1) with exception to TJC/SJC. Independent from the number of affected joints, at week 24 no differences between the response behaviour were seen between UST (UST+PBO) or UST+MTX. By trend, UST+PBO showed better response in oligoarthritis and polyarthritis with &gt;10 joints affected, whereas polyarthritis with affected joints &gt;5 and &lt;10 joints showed similar results for UST+PBO and UST+MTX (figure 1). <h3>Conclusion</h3> IL12/23 inhibition with UST is an effective treatment for active PsA independent of MTX use. Data from this subgroup analysis of the IIT indicate that additional MTX has no positive impact on UST efficacy, especially in focus on the arthritic PsA phenotype independent from the number of affected joints. <h3>REFERENCES:</h3> NIL. <h3>Acknowledgements:</h3> NIL. <h3>Disclosure of Interests</h3> Michaela Köhm Speakers bureau: Janssen, UCB, Novartis, Pfizer, Consultant of: Janssen, UCB, Novartis, Pfizer, Grant/research support from: Janssen, UCB, Novartis, Pfizer, GSK, BMS, Ann Christina Foldenauer Grant/research support from: Janssen, UCB, Novartis, Pfizer, GSK, BMS, Tanja Rossmanith Grant/research support from: Janssen, UCB, Novartis, Pfizer, GSK, BMS, Herbert Kellner: None declared, Uta Kiltz: None declared, Arnd Kleyer: None declared, Gerd Rüdiger Burmester: None declared, Jan Brandt-Juergens: None declared, David M Kofler: None declared, Harald Burkhardt Speakers bureau: Janssen, UCB, Novartis, Pfizer, GSK, BMS, Consultant of: Janssen, UCB, Novartis, Pfizer, GSK, BMS, Grant/research support from: Janssen, UCB, Novartis, Pfizer, GSK, BMS, Frank Behrens Speakers bureau: Janssen, UCB, Novartis, Pfizer, GSK, BMS, Consultant of: Janssen, UCB, Novartis, Pfizer, GSK, BMS, Grant/research support from: Janssen, UCB, Novartis, Pfizer, GSK, BMS.